Andrzej Sałata, Danuta Kozak

Abstract: The present study investigated different methods of propagation of the rhubarb cultivar ‘Karpow Lipskiego’: vegetatively from tissue cultures and by division of the mother plant as well as generatively from seed. The study also evaluated the usefulness of propagation material for establishing a rhubarb plantation. To produce in vitro plantlets, shoots were placed on modified Murashige and Skoog medium containing different cytokinins: benzyladenine (BA – 4.4, 11.1, 22.2 µmol·dm-3), kinetin (4.7, 11.6, 23.3 µmol·dm-3), isopentenyl adenine (2iP – 4.9, 12.3, 24.4 µmol·dm-3) as well as on control medium without growth regulators. Cuttings were obtained by division of crowns, while seedlings from seeds. In the period 2004–2006, vegetatively and generatively propagated plants were grown in a nursery. The obtained propagation material was used to establish a rhubarb plantation. Yield of field-grown plants was evaluated in the years 2007–2009. In the first year of cultivation in the nursery, plants propagated in vitro in the medium with the addition of kinetin at a concentration of 11.6 μmol dm-3 or 2iP at 12.3 μmol dm-3 developed crowns with the highest average weight of 1.48 and 1.05 kg, respectively. In the second year of cultivation in the nursery in the treatment with grown regulators applied, the average rhubarb crown weight ranged from 2.51 to 3.33 kg, while for the control treatment it was 1.78 kg. To characterize the population of in vitro plants, they were compared with plants obtained by division of the mother plant and from seeds. Plants propagated vegetatively from in vitro plantlets produced crowns with the highest average weight (0.83 kg), followed by those obtained from division of mother plants (0.79 kg), while plants produced from seeds had crowns with a much lower average weight (0.54 kg). In the second year of cultivation in the nursery, vegetatively and generatively propagated plants were characterized by a similar size and greater uniformity than in the first year. In the first year of planting (2007), petiole yield obtained from micropropagated plants was higher by 0.7 kg·plant-1 compared to generatively propagated plants, whereas in the second year of cultivation this difference was smaller and amounted to 0.6 kg· plant-1. In the third year of the plantation, plant productivity was more equal. During the study years, by far fewer leaves were harvested from generatively propagated plants compared to plants propagated vegetatively. In the second and third year of the plantation, intensive plant growth was observed; in effect, there were no significant relationships between petiole length and width and propagation method. The cultivation of vegetatively propagated plants gave the best effects in productivity; the average petiole yield was higher by 13.3 t·ha-1 in the case of micropropagation and by 16.0 t·ha-1 in the case of division of the mother plant compared to the yield obtained from rhubarb cultivation from seeds. Early yield at a level of 11.2 t·ha-1 was obtained from tissue cultured plants and its proportion accounted for 25% of total petiole yield.